The proposed studies are designed to examine the neuropsychological processes underlying the deficits in stem-completion and paired-associate priming exhibited by patients with dementia of the Alzheimer type (DAT). Since such long-term priming is intact in patients with circumscribed amnesia and in patients with other forms of dementia,identification of the processes associated with the impaired priming in DAT may lead to information about the necessary and sufficient conditions for the priming phenomenon to occur. In addition, by examining the processes underlying the priming deficit in mildly demented DAT patients, the present project may provide the information about the clinical utility of the priming phenomenon for the differential diagnosis of DAT. The first set of experi-ments will examine the effect of semantic orienting tasks on the verbal priming of DAT patients. The relationship of vigilance, selective attention and arousal to the priming performance of DAT patients will be examined in the second set of experiments. A third set of experiments will examine the role of visuoperceptual processes in the priming deficit of DAT patients.